Suppose you are working for a regional residential natural gas utility. For a sa

Question

Suppose you are working for a regional residential natural gas utility. For a sample of 90 customer visits, the staff time per reported gas leak has a mean of 211 minutes and standard deviation 31 minutes. The VP of network maintenance hypothesizes that the average staff tme devoted to reported gas leaks is 219 minutes At a 10 percent level of significance, what is the lower bound of the interval for determining whether to accept or reject the VP's hypothesis? Note that the correct answer will be evaluated based on the z-values in the summary table in the Teaching Materials section. Please round your answer to the nearest tenth. Note that the correct answer will be evaluated based on the full-precision result you would obtain using Excel.

Explanation / Answer

for 10 % significance level , z = 1.645

confidence interval

(Xbar - z * sd / sqrt(n) , Xbar + z * sd / sqrt(n))

= ( 211 - 1.645 * 31 /sqrt(90) , 211 + 1.645 * 31 /sqrt(90))

= ( 205.6246 ,216.37534)

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.